This invention relates to the field of preparing and testing materials used in electrochemical cells. More particularly, the invention relates to methods and apparatus for rapidly preparing electrodes and electrochemical cells, and evaluating electrochemical performance characteristics of electrode materials and/or electrolytes.
Manufacturers of electrochemical cells routinely search for electrode materials and electrolytes which provide improved electrochemical performance characteristics. Typically, new materials are tested by incorporating the new materials in individual test cells, each of which comprises a housing into which electrodes are installed and electrolyte is added. Conventional methods for fabricating and testing new materials, such as electrode materials and electrolytes, in electrochemical test cells is relatively time consuming and expensive, and limits the ability of researchers to test a large array of different materials and/or examine electrochemical performance characteristics of electrolyte materials under various conditions and/or while varying parameters such as electrolyte composition, electrode composition, current density, etc.
Therefore, there is a need for methods and apparatus that allow more efficient preparation and testing of large arrays of electrochemical cells to evaluate electrochemical cell performance as a function of electrode composition, electrolyte composition, and/or as a function of various other parameters.
The invention is directed to novel apparatuses and methods for more rapidly, and at a reduced cost, preparing and testing a large number of electrode materials. The invention allows various electrochemical cell performance characteristics to be more quickly evaluated as a function of composition, concentration, and/or various other parameters.
In accordance with an aspect of this invention, there is provided an apparatus comprised of a base or substrate carrying a plurality of electrodes, and at least one housing member that is secured to the base or substrate to define a cell volume for holding an electrolyte in contact with one or more of the plurality of electrodes. A counter electrode is disposed in the cell volume.
In accordance with another aspect of the invention a process for electrochemically depositing a material on a plurality of separate electrodes is provided. The same material or different materials may be deposited on each of the electrodes. The process involves first preparing an electrochemical cell volume. This is achieved by the steps of providing a base carrying a plurality of electrodes, providing a housing member that is attachable to the base to define a cell volume for holding an electrolyte in contact with one or more of the electrodes carried on the base, and attaching the housing member to the base to provide a cell volume for holding an electrolyte in contact with one or more of the electrodes carried on the base. A counter electrode is positioned in the cell volume, and an electrolyte is dispensed into the cell volume so that the electrolyte contacts the counter electrode and at least one of the electrodes carried on the base to provide a medium for ion transport between the counter electrode and the at least one electrode carried on the base. Thereafter, deposition of a material on the at least one electrode is achieved by electrically connecting the at least one electrode carried on the base with the counter electrode through an electrical circuit, and inducing an electrical current to flow through the circuit to cause electrochemical deposition of a material on the at least one electrode carried on the base.
Another aspect of the invention pertains to a process for electrochemically characterizing a material. The process involves first preparing an electrochemical cell having a material that is to be electrochemically characterized on an electrode. In accordance with the invention, this is achieved by providing a base carrying a plurality of electrodes, providing a housing member that is attachable to the base to define a cell volume for holding an electrolyte in contact with one or more of the electrodes carried on the base, and attaching the housing member to the base to provide a cell volume for holding an electrolyte in contact with one or more of the electrodes carried on the base. A counter electrode is positioned in the cell volume, and an electrolyte is dispensed into the cell volume so that the electrolyte contacts the counter electrode and at least one of the electrodes carried on the base to provide a medium for ion transport between the counter electrode and the at least one electrode carried on the base. Thereafter, the deposited material is characterized by electrically connecting the at least one electrode carried on the base and carrying a deposited material with the counter electrode through an electrical circuit, and measuring an electrical response of the electrical circuit.
In accordance with another aspect of the invention, an apparatus is provided for forming a plurality of test electrodes. The apparatus includes a base, and a plurality of electrode holders affixed to the base. A working electrode is releasably affixed to each of the electrode holders. A working electrode housing is also affixed to each of the electrode holders. Each electrode holder together with the housing defines an electrolytic cell volume for containing a plating bath electrolyte. A counter electrode is disposed in each of the electrolytic cells. The apparatus can be used for electrolytic deposition of materials from a plating bath electrolyte onto the working electrode to form a plurality of test electrodes which may be subsequently used in an electrochemical cell to evaluate the electrochemical performance characteristics of the deposited materials as a function of composition, and/or to evaluate the electrochemical performance characteristics of a particular deposited electrode material as a function of various parameters, such as electrolyte composition.
Another aspect of the invention involves a method of preparing a plurality of test electrodes by depositing an electrode material on each of a plurality of working electrodes. The method involves providing a base having a plurality of electrode holders and affixing a working electrode to each of the electrode holders. A working electrode housing is affixed to each of the electrode holders. Each electrode holder together with the affixed housing and affixed working electrode define an electrolytic cell. A counter electrode is positioned in each of the electrolytic cells. A plating bath electrolyte is introduced into each of the electrolytic cells. Each plating bath electrolyte contains a material which is capable of being electrochemically deposited on the working electrode. Thereafter, an electrical potential is applied between the working electrode and the counter electrode of each electrolytic cell to electrolytically deposit electrode material onto the working electrode.
In accordance with another aspect of the invention, an apparatus for testing electrochemical cell materials is provided. The apparatus includes a base having a plurality of electrode holders. A test electrode is releasably affixed to each electrode holder, an a test apparatus housing is mounted on the base to define an electrochemical cell in which each of the test electrodes is located. A counter electrode is located in the electrochemical cell.
In accordance with a further aspect of the invention, a method of testing electrode materials is provided. The method involves providing a base having a plurality of electrode holders and affixing a test electrode to each of the electrode holders. A test apparatus housing is mounted on the base to define an electrochemical cell in which each of the test electrodes is located. A counter electrode is positioned in the electrochemical cell, and an electrolyte is introduced into the electrochemical cell. Performance characteristics of each of the test electrodes is evaluated by measuring characteristics of an electrical circuit connecting the counter electrode with each of the test electrodes.